Abstract: We carried out behavioral observations on the Père David s deer (Elaphurus davidianus) stags in the Beijing Milu Park to investigate the vocal display and mating success in different social rank-classes during rut.The stags were classified into three rank-classes according to their rutting behavior:"harem master","challenger" and "bachelor".Bellowing,herding and mating were recorded in 12 stags:4 harem masters,5 challengers and 3 bachelors.The effectiveness value (E) were defined,that is E=A/T,to assess the effectiveness of herding or mating attempts made by stags (T represents the frequency of herding or mating attempts made by stag and A represents the frequency of herding or mating accepted by hinds).Results exhibited that:1)Frequency of bellowing,herding or mating showed significantly differences among "harem masters","challengers" and "bachelors"(P<0.05).2)Effectiveness value of herding also differed significantly among "harem masters","challengers" and "bachelors" (P<0.05).3)Effectiveness value of mating was significantly different between harem masters and challengers (P<0.05).We conclude that bellowing of Père David s deer stags strongly associates with its rank-class,and rank-class affects the mating success of stag directly.In addition,we recorded another new vocal display pattern in stags—barking,which was only recorded in hinds previously (Wemmer et al.,1983).